These problems can be mitigated through the process of design, which is an intellectual approach that emphasizes empathy, abductive reasoning, and rapid prototyping. Horst Rittel, one of the first to formalize a theory of wicked problems, cites ten characteristics of these complicated social issues Rittel, Horst. Dilemmas in a General Theory of Planning.. Policy Sciences, 1973: 155-169.
Changes in blood pressure and volume are not nearly as sensitive a stimulator as increased osmolarity, but are nonetheless potent in severe conditions. For example, Loss of 15 or 20% of blood volume by hemorrhage results in massive secretion of antidiuretic hormone.
This stimulates renin release by the kidney, which increases circulating angiotensin II (AII) and aldosterone. These hormones increase blood volume by enhancing renal reabsorption of sodium and water. Increased AII also causes systemic vasoconstriction and enhances sympathetic activity.ncreased secretion of aldosterone generally results from adrenal adenoma or adrenal hyperplasia. Increased circulating aldosterone causes renal retention of sodium and water (see figure), so blood volume and arterial pressure increase.